This application claims priority of Taiwan Patent Application No. 89217298, filed on Oct. 5, 2000.
1. Field of the Invention
The invention relates to a labeling machine, more particularly to a labeling machine that is capable of detection of defective products and automatic removal of the defective products at a take-out end of a conveying unit thereof.
2. Description of the Related Art
Commodities, such as beverage bottles, drug bottles, containers, and packaging boxes, are generally provided with a label to classify products, to indicate usage and other information, to display the trademark or logo of the manufacturer, etc. With the recent advancement in automation, automated attachment of labels to such commodities has taken the place of manual label attachment, and has become quite popular in the industry.
In a conventional labeling machine, a reel of labels is arranged on a reel supporting plate. A leading edge of the reel is drawn via a driving device to a label applicator plate where the labels are applied to containers being advanced by a container conveying unit. However, the conventional labeling machine cannot effectively overcome problems associated with the detection of defective containers that are not properly labeled, and the removal of the same.
In a label reel, a series of adhesive-backed labels are adhered to a waxed backing paper strip. Referring to FIG. 1, under normal conditions, the labels should be spaced apart from each other by a uniform clearance, and there should not be any missing label. Moreover, the bar codes or batch information on the labels should be correctly printed. The conventional labeling machine, as a matter of fact, is unable to automatically detect containers that are not properly labeled, and has to rely upon manual inspection for removing the defective containers. Although there is available image comparison equipment to detect containers attached with defective labels, it is very expensive, complicated in construction, and operable only by skilled personnel.
The applicant has made various improvements on the labeling machine and has filed applications therefor in the United States. In co-pending U.S. Ser. No. 09/767,781, the applicant discloses a label applying unit for a labeling machine and suitable for applying labels of different lengths in automated operations. In co-pending U.S. Ser. No. 09/767,783, the applicant describes a labeling machine that is capable of preventing erroneous attachment of labels to containers. In co-pending U.S. Ser. No. 09/767,780, the applicant teaches a label-sensing device for a labeling machine that is adjustable to suit the actual ambient light condition. In co-pending U.S. Ser. No. 09/768,100, the applicant discloses a labeling machine with a container spacer device that can appropriately adjust a spacing between adjacent containers during a label attachment operation. In co-pending U.S. Ser. No. 09/768,114, the applicant teaches a labeling machine that is capable of attaching labels precisely to different sizes of containers. The contents of the aforesaid patent applications are incorporated herein by reference.
Therefore, the main object of the present invention is to provide a labeling machine that is capable of automatic detection of defective products and removal of the same at a take-out end of a conveying unit.
Accordingly, the labeling machine of the present invention includes:
a motor-driven container conveying unit having a feed-in end and a take-out end, the conveying unit being adapted to convey a plurality of containers from the feed-in end to the take-out end;
a label applying unit disposed adjacent to the conveying unit between the feed-in and take-out ends, and operable so as to be adapted to attach labels on the containers being conveyed by the conveying unit, the label applying unit including
a reel support plate adapted to support a label reel thereon, the label reel including a backing paper strip and a plurality of the labels releasably and successively adhered on the backing paper strip, each of the labels having a bar code printed thereon,
a label applicator plate adapted to release the labels from the backing paper strip for application to the containers being conveyed by the conveying unit, and
a motor-driven feed roller unit disposed between the reel support plate and the label applicator plate and operable so as to feed one end of the label reel on the reel support plate to the label applicator plate;
a container sensor disposed anterior to the label applicator plate relative to an advancing route of the label reel, and adapted to generate a container detect signal upon detection of one of the containers being conveyed by the conveying unit;
a controller coupled electrically to the feed roller unit and the container sensor, the controller activating the feed roller unit in accordance with the container detect signal from the container sensor so as to advance the label reel for attaching one of the labels onto said one of the containers detected by the container sensor and being conveyed by the conveying unit;
a container removal unit coupled electrically to the controller, disposed posterior to the label applicator plate relative to the advancing route of the label reel, and operable so as to remove one of the containers at the take-out end of the conveying unit;
a bar code sensor coupled electrically to the controller, disposed adjacent to the advancing route of the label reel between the reel support plate and the label applicator plate, and adapted to sense the bar codes on the labels of the label reel and to generate corresponding bar code data;
the controller comparing the bar code data from the bar code sensor with predetermined bar code data and, upon detection by the controller that the bar code data of one of the labels does not match the predetermined bar code data, the controller timely activating the container removal unit so as to remove one of the containers at the take-out end that was attached with said one of the labels whose bar code data does not match the predetermined bar code data;
a label sensor coupled electrically to the controller and disposed adjacent to the advancing route of the label reel between the reel support plate and the label applicator plate, the label sensor generating a first signal upon detection of a part of the backing paper strip having one of the labels adhered thereon, and further generating a second signal upon detection of another part of the backing paper strip having none of the labels adhered thereon;
wherein upon detection by the controller that the duration of the second signal from the label sensor has exceeded a predetermined threshold, indicating that a portion of the label reel has none of the labels adhered thereon, the controller timely activating the container removal unit so as to remove one of the containers at the take-out end that was not attached with any one of the labels;
a printing unit disposed adjacent to the advancing route of the label reel between the reel support plate and the label applicator plate, and adapted to print batch information on the labels of the label reel; and
a batch information sensor coupled electrically to the controller, disposed adjacent to the advancing route of the label reel between the printing unit and the label applicator plate, and adapted to sense the batch information that was printed on the labels of the label reel and to generate corresponding batch information data;
the controller comparing the batch information data from the batch information sensor with predetermined batch information data and, upon detection by the controller that the batch information data of one of the labels does not match the predetermined batch information data, the controller timely activating the container removal unit so as to remove one of the containers at the take-out end that was attached with said one of the labels whose batch information data does not match the predetermined batch information data.